Study is directed toward increasing the service life of amalgam restorations. The most common cause of failure is embrittlement associated with galvanic corrosion of the Sn-Hg gamma-2 alloy phase. Laboratory corrosion cells with aqueous sodium sulfidechloride electrolyte, graphite and amalgam electrodes, simulate the oral corrosion process. Base-line data are being obtained on commercial amalgams at various mercury contents. Laboratory spherical alloys of high Ag and Cu contents can be heat treated to meet expansion specifications with smaller quantities and finer distribution of the corrosion-prone gamma-2phase. Amalgams from these experimental alloys will betested for corrosion behavior and strength properties. Amalgam patches can be metallurgically bonded even to severely corroded restorations by dry mix condensing techniques using small increments. Temperature changes in the mouth induce thermal expansion stresses which weaken the bond. Permissable limits of temperature cycling will be determined and improvements sought in bond metallurgy and clinical technique.